The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Air induction systems typically utilize clean air ducts to convey filtered air from an airbox assembly to a throttle body, before delivering the filtered air to a vehicle engine. The clean air duct must be closed to the outside environment to prevent false air from entering the system. False air is any air that enters the system through leaks created within a part or at assembly interconnections of the parts of the system.
Historically, clean air ducts have been molded completely from rubber or rubber alternatives. While such a manufactured product allows for relatively easy attachment to the airbox and throttle body, it also causes concerns related to excess weight and duct integrity or collapsibility. Recent developments have improved upon the complete rubber design by making use of overmolding technology to create a combination blow molded duct with overmolded rubber cuffs. While such a duct results in a lighter duct, the combination of blow molding and overmolding does not allow for tight or close part tolerances. In overmolding, a die must close securely around the blow molded part with no air leaks thus requiring the use of a mandrel inserted into the part to center it and use of a ledge and space around the part circumference to clamp the rigid part prior to overmolding. In order to incorporate the necessary ledge, a part designer must provide additional length in the part design. This additional length may result in space between the blow-molded and overmolded parts. Tight packaging within current automotive vehicles requires that an alternative configuration be developed to achieve the desired performance in a smaller package. Noise, vibration and harshness (“NVH”) concerns must also be considered with any clean air duct designs. Forceful turbulent air entering the induction system may generate an undesirable “whoosh” or “whistle” noise as a result of the forceful air moving through the clean air duct. Thus, the new configuration must be securely held together and be resistant to separation due to the air forces.
FIG. 6 depicts a connection 100 of a blow molded clean air duct 102 that has an overmolded cuff 104 mated at the interface 110. Finally the cuff 104 is pressed onto the throttle body 106 as part of the connection 100. In the prior art connection 100, a gap or space 108 remains due to the mandrel utilized in the overmolding process. Such space 108 utilizes valuable space necessary under the hood of today's automobiles for various vehicle and engine systems.
What is needed then is a device that does not suffer from the above disadvantages. This, in turn, will provide a device with an interconnection or joint between an expansion chamber and a clean air duct cuff that is capable of withstanding the forces due to internal airflow and overpressure of the intake system, and that can be made efficiently and compactly without spaces remaining after tooling withdrawal. Additionally, the part should easily and securely join to a throttle body and provide flexibility in response to the force of airflow.